The invention relates to improvements in preamble codes used in Orthogonal Frequency Division Multiple Access (OFDMA) for the physical layer (PHY).
The invention may be used, for example, to improve the communication performance in systems within the IEEE 802.16 Standard for Broadband Wireless Access. Such improvements may better adapt the OFDMA to a mobile environment.
The improvements may be used in the OFDMA PHY/MAC layers.
An important parameter in such communications is the Peak to Average Power Ratio (PAPR). Wideband signals may exhibit high values of PAPR, which pose high demands on the linearity performance of the system. That is, a large dynamic range is required to convey the high amplitude peaks associated with such signals.
It may be highly desirable to reduce the PAPR, to allow improved performance while concurrently reducing the costs of communication systems.
It is important to achieve improved performance in short codes, of length 128, 512 and 1K, in the preamble.
The communications may use various Fast Fourier Transform (FFT) values, thus improvements preferably should be capable at operating at these values.